[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/layers/content_layer.cc

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/content_layer.h"
 
 #include "base/auto_reset.h"
 #include "base/metrics/histogram.h"
 #include "base/time/time.h"
 #include "cc/layers/content_layer_client.h"
 #include "cc/resources/bitmap_content_layer_updater.h"
 #include "cc/resources/bitmap_skpicture_content_layer_updater.h"
 #include "cc/resources/layer_painter.h"
 #include "cc/trees/layer_tree_host.h"
 
 namespace cc {
 
 ContentLayerPainter::ContentLayerPainter(ContentLayerClient* client)
     : client_(client) {}
 
 scoped_ptr<ContentLayerPainter> ContentLayerPainter::Create(
     ContentLayerClient* client) {
   return make_scoped_ptr(new ContentLayerPainter(client));
 }
 
 void ContentLayerPainter::Paint(SkCanvas* canvas,
-                                gfx::Rect content_rect,
+                                const gfx::Rect& content_rect,
                                 gfx::RectF* opaque) {
   base::TimeTicks paint_start = base::TimeTicks::HighResNow();
   client_->PaintContents(canvas, content_rect, opaque);
   base::TimeTicks paint_end = base::TimeTicks::HighResNow();
   // The start and end times might be the same if the paint was very fast or if
   // our timer granularity is poor. Treat this as a very short time duration
   // instead of none to avoid dividing by zero.
   if (paint_end == paint_start)
     paint_end += base::TimeDelta::FromMicroseconds(1);
 
@@ skipping 127 matching lines @@
   return picture;
 }
 
 void ContentLayer::OnOutputSurfaceCreated() {
   SetTextureFormat(
       layer_tree_host()->GetRendererCapabilities().best_texture_format);
   TiledLayer::OnOutputSurfaceCreated();
 }
 
 }  // namespace cc